Positioning Leadership

APN-049 Rev 1 September 11, 2008

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SUPERSTAR II Messages for OEMV

OEMV 3.500 introduces the ability to use SUPERSTAR II (SSII) ID #20, #21 and #33

messages on OEMV cards. We added this functionality to simplify interoperability with

SSII products and to ease transition from SSII to OEMV.

NovAtel discontinued the SSII family of products and the last order date has passed.

NovAtel will continue to provide technical services and repairs until June 30, 2011.

Behavioral Changes

Details on Message IDs #20, #21 and #33 are in the L1 GPS Firmware Reference

Manual, available on our website. This application note adds information about OEMV-

specific behavioral changes. The behavioral changes are:

• Message ID #20 and Message ID #21 always report the WGS84 datum type, even

if another datum was used

• Message ID #33 only reports in-view satellites above the elevation cut-off angle

• SSII self-test and initialization system modes do not exist on an OEMV

• Sets ‘Differential Corrections Available’ flag, in Message ID #33, to ‘ON’ if the

observation used in the filter had differential corrections applied to it, so there

may be observations that have differential corrections available but are not

flagged if the receiver does not use them in the solution

• Number of satellites in the solution may exceed 12 since the OEMV has more

channels (16) than the SSII (12)

• Message ID #33 only reports on GPS and SBAS satellites, even if the solution

uses GLONASS satellites

• OEMV’s Dilution of Precision (DOP) replaces SSII’s Figure of Merit (FOM)

OEMV Interface Configuration

These messages are for output only. Use only NovAtel commands to request these

messages and to configure the OEMV receiver. You cannot configure the receiver with

SSII binary commands.

To request Message ID #20 at 5 Hz, send this command:

LOG COM1 SSIIMSG20 ONTIME 0.2

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To request Message ID #21 at 5 Hz, send this command:

LOG COM1 SSIIMSG21 ONTIME 0.2

To request Message ID #33 at 1 Hz, send this command:

LOG COM1 SSIIMSG33 ONTIME 1

SSIIMSG20 and SSIIMSG21 are populated from the NovAtel BESTPOS and BESTXYZ

logs respectively. SSII NAV Modes, in Message ID #20 and Message ID #21, correspond

to certain position mode, and solution status, values in BESTPOS and BESTXYZ.

Specifically:

SSII NAV Mode 2: NAV 3-D

corresponds to OEMV Position Type: SINGLE

SSII NAV Mode 4: Differential 3-D and Differential Source Selection 0: SBAS

corresponds to OEMV Position Type: WAAS

SSII NAV Mode 4: Differential 3-D and Differential Source Selection 1: DGPS

corresponds to OEMV Position Type: PSRDIFF

SSII NAV Mode 0: Initialization Required

corresponds to OEMV Solution Status: INSUFFICIENT_OBS

SSII NAV Mode 3: Altitude Hold (NAV 2-D)

corresponds to OEMV Position Type: FIXEDHEIGHT

SSII NAV Mode 8: Base Station

corresponds to OEMV Position Type: FIXEDPOS